Systemic Inflammatory Indexes as Predictors of Delirium, Thromboembolic Events, and Mortality After Hip Fracture and Major Orthopedic Surgery: A Meta-Analysis

BACKGROUND: Hip fractures and other orthopedic surgeries are often associated with poor post-operative outcomes, including thrombus formation, delirium, and mortality. Systemic inflammatory markers, such as the systemic immune-inflammatory index (SII) and systemic inflammation response index (SIRI), have shown potential for predicting adverse outcomes in cancer and cardiovascular diseases. This meta-analysis evaluates the predictive value of SII and SIRI for complications following orthopedic surgeries, aiming to establish them as practical tools for risk stratification to assist the surgeons' decision for optimal treatments. METHODS: A systematic search was conducted in PubMed, Embase, and Web of Science through January 2025, adhering to PRISMA guidelines. Cohort studies reporting the relationship between pre-operative SII/SIRI and post-operative complications were included. Outcomes included thrombus formation, delirium, and mortality. Random-effects models were used for meta-analyses, and heterogeneity was assessed with I² statistics. Sensitivity analyses were performed to mitigate the heterogeneity. RESULTS: < 0.001). Sensitivity analysis suggested a potential association, but statistical significance was not achieved. CONCLUSION: SII and SIRI show promise as predictors for post-operative delirium but have limited evidence for thrombus formation or mortality. Future research should focus on prospective studies with standardized cut-offs to validate their clinical utility.